Brequelle Smith 12-2-13 Periods 1-2 Radish lab Report Question: Is there a difference in the biomass and height

of radish seeds grown in either light or darkness?

Hypothesis: If we grow 0.5g of radish seeds in the dark and 0.5g in the light, then I think that

the radishes in the light will gain 0.2g in biomass, I also think that the dark radishes will have no change in biomass because for a plant to photosynthesize they need light to produce glucose to grow.Procedure: 1. First measure out 0.5g of radish seeds and we gently spread the seeds over four layers of a moist paper towel that is in a petri dish. We labeled this dish light. 2. Repeat the first step, but instead of labeling it light label it dark. 3. After these steps place the light dish under the grow lights and the dark in a place were no light can get in. 4. Every day we put 10mL of water in each dish. After a full week the seeds should have grown. 5. Being extremely careful find the longest stem for both the light and the dark dish, measure that seed from the beginning of the stem to the end of the stem using cm. 6. Then we put the seedling in an envelope. Label the envelope with the weight of the envelope, the height of the longest stem, there must also be whether or not the seeds were in the light or the dark. Even though you dont know yet leave room for seeds final biomass and the change in the seeds bio mass.

7. Let the envelope dry for 24 hours. After the 24hr period then take the biomass of the envelope and subtract the original weight of the envelope to get the final biomass. Data: Light Dark

Average in Biomass of Radishes after 7 days

Results: The data shows us that the dark radish seeds lost weight after the 7 day period. When we took the seeds out the dark had a light yellowish color to them. When the heights of radish seeds were measured the dark seeds were 4.5cm. the light seeds looked very different, they had green leafs and short stems. The lights average height was 1.4cm. The biomass of the dark seeds is -0.13g and the light is 0.26g. Discussion: I thought the light radishes would weigh more than the dark, and be taller because it has all of the materials to photosynthesize, but the data didnt support my hypothesis. In height the dark radish seeds are 4.6cm. This shows us that the seeds grown in the dark were respiring which means they were eating the energy in the seed to grow, and they werent able to photosynthesize. The radishes grown in the light are 1.4cm tall. This shows us that they were stocking up on cells instead of using there backup resource.

I was correct on the biomass of the plants, the dark seeds lost weight and there final biomass was -0.13g the light gained biomass and weighed 0.2g. The reason that the dark seeds lost weight was because they ate the energy from there seed instead of eating the energy from the light, this is called cellular respiration.

Conclusion: We wanted to know if there is a difference in the weight and growth of radish seeds in either light or darkness. I learned what cellular respiration means I was also able to see it in the radish seeds. There might have been a few glitches in the data because when we took the dark seeds out of the dark to weigh and measure them they could have gotten energy from the light. Another problem was that we started the project on a Friday and we werent able to water them over the weekend. If I was able to do this experiment again I would use other seeds like pumpkin and squash. I would like to experiment with this because of another question I had. Which was, does the difference in seeds being grown in the light and being grown in dark the same with other seeds?